This application relates generally to measuring systems and more specifically relates to improving measurement capability by using a coordinate measuring system.
Linear encoders are frequently used wherever high precision measurements are required. Linear encoders are often affixed to high precision, numerically controlled machine tools. A critical element of these machine tool designs are their measuring systems. The measuring system""s resolution and accuracy must be adequate for the task and the positioning of the measuring system relative to the point of interest is important to avoid measurement errors. Lasers in a vacuum have been favored in the past because they represented the state-of-the-art in measurement capability. However, the cost of a laser system may be excessive.
Aspects of the present invention include a system comprising: a first periodic measurement scale assembly substantially aligned with a first axis; and a first plurality of sensors positioned substantially proximate to the first periodic measurement scale assembly, the first plurality of sensors including a pair of sensors spaced from each other along the first axis and configured to cooperatively measure at least one of departure from straightness of a first effective point from the first axis and angular displacement of the first effective point from the first axis.
Aspects of the present invention further include the first plurality of sensors having at least one sensor configured to measure linear displacement of a first effective point along the first axis.
Aspects of the present invention further include a second periodic measurement scale assembly substantially aligned with a second axis substantially orthogonal to the first axis; and a second plurality of sensors positioned in proximity to said second periodic measurement scale assembly, with the second plurality of sensors including at least one sensor configured to measure displacement of a second effective point along the second axis, and a pair of sensors spaced from each other along the second axis and configured to cooperatively measure at least one of departure from straightness of the second effective point from the second axis, and angular displacement of the second effective point from the second axis.
Aspects of the present invention further include measuring at least one of departure from straightness of a first effective point from a first axis and angular displacement of the first effective point from the first axis, by cooperatively utilizing a pair of sensors spaced from each other along the first axis and positioned substantially proximate a first scale assembly substantially aligned with the first axis.
Aspects of the present invention further include measuring linear displacement of the first effective point along the first axis by using at least one sensor positioned substantially proximate the first scale assembly.
Aspects of the present invention further include measuring displacement of a second effective point along a second axis using at least one sensor positioned substantially proximate a second scale assembly; measuring at least one of departure from straightness of the second effective point from the second axis and angular displacement of the second effective point from the second axis, by cooperatively using a pair of sensors spaced apart from each other long the second axis and positioned substantially proximate the second scale assembly.
Aspects of the present invention further include a first scale assembly having a plurality of first periodic measurement scales substantially aligned with a first axis; and a first plurality of pairs of sensors positioned in substantial proximity to said first scale assembly, said first plurality of pairs of sensors including a first pair of sensors spaced from each other along the first axis and configured to cooperatively measure departure from straightness of a first effective point from the first axis.
Aspects of the present invention further include a position measuring device comprising: a plurality of first periodic measurement scales substantially aligned with a first axis; and a first plurality of sensors positioned substantially proximate to said plurality of first periodic measurement scales, said first plurality of sensors including at least one sensor configured to measure linear displacement of a first effective point along the first axis, and a pair of sensors spaced from each other along the first axis and configured to cooperatively measure departure from straightness of the first effective point from the first axis, and angular displacement of the first effective point from the first axis.
Aspects of the present invention further include a machine tool comprising: a first scale assembly having a first periodic measurement scale aligned with a first axis; and a firs plurality of sensors positioned in proximity to said first scale assembly, said first plurality of sensors including a pair of sensors spaced from each other along the first axis and configured to cooperatively measure at least one of departure from straightness of a first effective point from the first axis and angular displacement of the first effective point from the first axis.
Aspects of the present invention further include a method of determining the position of a rigid body comprising: measuring linear displacement of a first effective point along a plurality of measurement scales substantially aligned along a first axis by cooperatively using a first pair of sensors positioned substantially proximate said plurality of measurement scales; and measuring at least one of departure from straightness of the first effective point from the first axis and angular displacement of the first effective point from the first axis, by cooperatively using a second pair of sensors spaced apart from each other along the first axis and positioned substantially proximate said plurality of measurement scales.
Aspects of the present invention further include an apparatus comprising: means for measuring at least one of departure from straightness and angular displacement of a first effective point from a first axis by cooperatively using a pair of sensors spaced from each other along said first axis and positioned substantially proximate a first scale assembly substantially aligned with said first axis.
Aspects of the present invention further include a measuring device comprising: means for measuring linear displacement of a first effective point along a plurality of measurement scales aligned along a first axis by using a first pair of sensors positioned substantially proximate said plurality of measurement scales; and means for measuring at least one of departure from straightness of the first effective point from the first axis and angular displacement of the first effective point from the first axis by cooperatively using a second pair of sensors positioned substantially proximate said plurality of measurement scales.
Aspects of the present invention further include a system comprising: first means for measuring a position of a rigid body relative to a reference body; and second means for measuring a position of an object relative to the reference body, with said object configured to act upon said rigid body wherein said second means is configured to compensate for errors in the position of the rigid body relative to the object.
Aspects of the present invention further include a system comprising: a first scale assembly substantially aligned with a first axis; a second scale assembly substantially aligned with a second axis; a first slide assembly having at least one sensor and designed to travel along and substantially proximate to said first scale assembly; a second slide assembly having at least one sensor and designed to travel along and substantially proximate to said second scale assembly, wherein one pair of the pair of scale assemblies and the pair of slide assemblies is fixed with respect to each other; and a control system configured to utilize data from said at least one sensor on said second slide assembly to compensate for errors in the positioning of a first effective point on the first slide assembly.
Aspects of the present invention further include a system comprising: a first scale assembly having a plurality of first periodic measurement scales substantially aligned with a first axis; a first plurality of pairs of sensors positioned substantially proximate to said first scale assembly said first plurality of pairs of sensors including at least one sensor configured to measure linear displacement of the first effective point along the first axis, and a pair of sensors spaced apart from each other and configured to cooperatively measure at least one of departure from straightness of a first effective point from the first axis and angular displacement of the first effective point from the first axis; a second scale assembly having a plurality of periodic measurement scales aligned with a second axis; a second plurality of pairs of sensors positioned substantially proximate to said second plurality of periodic measurement scales, said second plurality of pairs of sensors including at least one sensor configured to measure linear displacement of a second effective point along the second axis, and a pair of sensors spaced apart from each other and configured to cooperatively measure at least one of departure from straightness of the second effective point from the second axis, and angular displacement of the second effective point from the second axis; and wherein said second plurality of pairs of sensors are configured to compensate for errors in the positioning of a rigid body.